It is common for the driver of a vehicle to select a higher gear in order to optimise the fuel economy of the vehicle. Where the vehicle has an automatic transmission, a control unit of a vehicle can be configured to select an appropriate gear based on the speed of the vehicle and the driver's torque demand. The control unit will typically use an algorithm to optimise fuel economy, vehicle performance, or a combination of them both.
During an extended downhill decent, for example on a mountain road, the torque demand from the driver is usually very low. As a result, the control unit of the automatic transmission will select a high gear to optimise the fuel economy of the vehicle. However, the high gear selected by the control unit results in a low level of engine braking. The driver must therefore rely on the vehicle's brakes to decelerate the vehicle during the extended downhill decent.
Such use of the brakes may cause the brake pads of the brakes to wear out faster, which would lead to more frequent brake pad replacement. Furthermore, heavy use of the brakes during an extended downhill decent may lead to degradation of braking performance.